Monday, June 11, 2007

WeLcoMe Guys... to tHe Bikers 99...!!!

A motorcycle or motorbike is a single-track, two-wheeled motor vehicle powered by an engine. Styles of motorcycles vary depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions. In many parts of the world, motorcycles are among the least expensive and most widespread forms of motorised transport.

History

Replica of the Daimler-Maybach Reitwagen

Replica of the Daimler-Maybach Reitwagen

A 1913 Fabrique National in-line four with shaft drive from Belgium

A 1913 Fabrique National in-line four with shaft drive from Belgium

A  pre-war Polish Sokół 1000

The inspiration for arguably the first motorcycle was designed and built by the German inventors Gottlieb Daimler and Wilhelm Maybach in Bad Cannstatt (since 1905 a city district of Stuttgart) in 1885. The first petroleum-powered vehicle, it was essentially a motorized bicycle, although the inventors called their invention the Reitwagen ("riding car").

However, if one counts two wheels with steam propulsion as being a motorcycle, then the first one may have been American. One such machine was demonstrated at fairs and circuses in the eastern U.S. in 1867, built by Sylvester Howard Roper of Roxbury, Massachusetts.

In 1894, Hildebrand & Wolfmüller became the first motorcycle available for purchase. In the early period of motorcycle history, many producers of bicycles adapted their designs to accommodate the new internal combustion engine. As the engines became more powerful, and designs outgrew the bicycle origins, the number of motorcycle producers increased.

An historic 1941 Crocker

An historic 1941 Crocker

Until the First World War, the largest motorcycle manufacturer in the world was Indian, producing over 20,000 bikes per year. By 1920, this honour went to Harley-Davidson, with their motorcycles being sold by dealers in 67 countries, until 1928 when DKW took over as the largest manufacturer.

After the Second World War, the BSA Group became the largest producer of motorcycles in the world, producing up to 75,000 bikes a year in the 1950s. The German company NSU Motorenwerke AG held the position of largest manufacturer from 1955 until the 1970s.

From the 1960s through the 1990s, small two-stroke motorcycles were popular worldwide, partly as a result of East German Walter Kaaden's engine work in the 1950s.

Today, the Japanese manufacturers, Honda, Kawasaki, Suzuki, and Yamaha dominate the motorcycle industry, although Harley-Davidson still maintains a high degree of popularity in the United States. Recent years have also seen a resurgence in the popularity of several other brands sold in the U.S. market, including BMW, Triumph and Ducati.

Outside of the USA, these brands have enjoyed continued and sustained success, although Triumph, for example, has been re-incarnated from its former self into a modern world-class manufacturer. In overall numbers, however, the Chinese currently manufacture and sell more motorcycles than any other country and exports are rising. The quality of these machines is asserted to be somewhat lower than their Japanese, European and American counterparts.

Also, the small-capacity scooter is very popular through most of the world, and the Piaggio group of Italy, for example, is one of the worlds largest producers of two-wheeled vehicles. The scooter culture has, as yet, not been in adopted widely in North America.

In November 2006, the Dutch company E.V.A. Products BV Holland announced that its diesel-powered motorcycle, the Track T-800CDI, achieved production status.The Track T-800CDI uses a 800 cc three-cylinder Daimler Chrysler diesel engine. Other manufacturers, including Royal Enfield, had been producing diesel-powered bikes since at least the 1980s.

TeChniCaL AspecTs

Construction

A 1966 British motorbike - the 250 cc Ariel Leader used a pressed-steel frame

A 1966 British motorbike -
the 250 cc Ariel Leader used a pressed-steel frame

The construction of modern motorcycles has mostly standardized on the key components listed below.

Chassis

The chassis (or frame) of a motorcycle is typically made from welded aluminium or steel (or alloy) struts, with the rear suspension being an integral component in the design. Carbon-fiber and titanium are used in a few very expensive custom frames.

The chassis includes the head tube that holds the front fork and allows it to pivot. Some motorcycles include the engine as a load-bearing (or stressed) member; this has been used all through bike history but is now becoming more common.

Oil-in-Frame (OIF) chassis, where the lubricating oil is stored in the frame of the motorcycle, was used for Vincent motorcycles of the fifties, and for a while during the 1970s on some NVT British motorcycles. It was widely unpopular and generally regarded as a bad idea at the time. Today it is a widely used idea on "thumpers" (single-cylinder four-strokes) that usually have a dry-sump lubrication requiring an external oil tank. It has since gained some cache in modern (2006) custom bike world too because of the space saving it can afford and the reference to an earlier era. Buell motorcycles employ a similar design - the oil is held in the swingarm, while the fuel is held in the frame.

Front fork

A motorcycle fork is the portion of a motorcycle that holds the front wheel and allows one to steer. For handling, the front fork is the most critical part of a motorcycle. The combination of rake and trail determines how stable the motorcycle is.

A fork generally consists of two fork tubes (sometimes also referred to as forks), which hold the front wheel axle, and a triple tree, which connects the fork tubes and the handlebars to the frame with a pivot that allows for steering.

TecHnIcal AsPecTs 2

Final drive

A shaft final drive is housed within a rear swingarm of a BMW R1200GS

A shaft final drive is housed within a rear swingarm of a BMW R1200GS

Power transfer from the gearbox to the rear wheel is typically accomplished with a chain, which requires both lubrication and adjustment for elongation (stretch) that occurs through wear. The lubricant is subject to being thrown off the fast-moving chain and results in grime and dirt build up. Chains do deteriorate, and excessive wear on the front and rear sprockets can be dangerous. Many manufacturers offer cruiser models with final drive options of a belt or a shaft. A belt drive is still subject to stretch, but operates very quietly, cleanly, and efficiently. However, belt drives are limited in the amount of power they can transmit. A toothed belt is frequently used. A shaft drive is usually completely enclosed; the visual cue is a tube extending from the rear of the transmission to a bell housing on the rear wheel. Inside the bell housing a bevelled gear on the shaft mates with another on the wheel mount. This arrangement is superior in terms of noise and cleanliness, and is virtually maintenance free, with the exception of occasional fluid changes. However, the additional gearsets are a source of power loss and add weight.

Wheels

The wheel rims are usually steel or aluminium (generally with steel spokes and an aluminium hub) or mag-type cast or machined aluminium. At one time, motorcycles all used spoke wheels built up from separate components (see wheelbuilding), but, except for dirtbikes, one-piece wheels are more common now. Performance racing motorcycles often use carbon-fibre wheels, but the expense of these wheels is prohibitively high for general usage.

A wire wheel and pneumatic motorcycle tire on a Ural

A wire wheel and pneumatic motorcycle tire on a Ural

Wire wheels, a.k.a. "laced wheels," have a central hub connected to the rim of the wheel via spokes made of wire. These spokes are generally quite solid and will not easily bend as would typical wire cord. Nevertheless, they mechanically function as wires under tension, holding the rim true and providing strength to the wheel. Cast magnesium disks, produced by one-step hot forging from magnesium alloys ZK60 and MA-14, are also used for many motorcycle wheels.

tEcHniCaL aSpeCts 3

Transmission

The transmission on this 1921 ABC motorcycle is located behind the engine and shifts by a long hand-operated lever on its right side.

The transmission on this 1921 ABC motorcycle is located behind the engine and shifts by a long hand-operated lever on its right side.

Modern motorcycles normally have five or six forward gears. Only the largest touring motorcycles and a few models that are routinely used with a sidecar or converted to tricycle configuration are fitted with a reverse gear. On a few, including the Honda Gold Wing and BMW K1200LT, it is not really a reverse gear, but a feature of the starter motor which when reversed, performs the same function. The weight of these motorcycles, in excess of 360 kg (800 lbs), means that they cannot effectively be pushed backwards in some situations by a seated rider.

Older motorcycles had various kinds of shifting arrangements. A common version before World War II was a hand operated shift lever that rose from the transmission behind the engine up to beside the fuel tank on its left or right side. Later, some motorcycles, especially British, used foot shift levers that were located on the right side of the transmission. Today, shifting on the world's motorcycles has been standardized to the left-side foot-operated shift lever.

The clutch is typically an arrangement of plates stacked in alternating fashion, one geared on the inside to the engine and the next geared on the outside to the transmission input shaft. Whether wet (rotating in engine oil) or dry, the plates are squeezed together by a spring, causing friction build up between the plates until they rotate as a single unit, driving the transmission directly. A lever on the handlebar exploits mechanical advantage through a cable or hydraulic arrangement to release the clutch spring, allowing the engine to freewheel with respect to the transmission.

A typical 5-gear, foot-shift transmission on an HD Sportster

A typical 5-gear, foot-shift transmission on an HD Sportster

The most commonly used transmission is a sequential gearbox. From neutral, either first or second gear can be selected, but higher gears may only be accessed in order - it is not possible to shift from second gear to fourth gear without shifting through third gear. A five-speed of this configuration is commonly said to be "one down, four up," and a six-speed is said to be "one down, five up" due to the placement of the gears with relation to neutral. Neutral is considered to be "half a click" from first and second gears, so shifting directly between the two gears is made in one firm movement. Neutral is not placed "below" first gear to prevent the rider accidentally selecting neutral while attempting to downshift to first gear, possibly leading to an accident.

Scooters normally have a continuously variable transmission (CVT). The CVT is a type of automatic transmission (also occasionally used in cars) that can change the "gear ratio" (gears are not generally involved) to any one of the possible undetermined settings within a given range. The CVT is not constrained to a small number of gear ratios, such as the four to six forward ratios in typical automotive transmissions. CVTs are ideally suited to 2-wheeled vehicles because of the lack of shift shock. A conventional automatic transmission might shift shock at an unexpected moment and upset the vehicle. The CVT transmission also offers maximum power efficiency, an important factor for the engines with less than 100 cc capacity typically used in scooters.

TeChniCaL asPecTs 4

Engine

Almost all commercially available motorcycles are driven by conventional gasoline internal combustion engines, but some small scooter-type models use an electric motor, and a very small number of diesel models exist (e.g., the USMC M1030 M1 version of the Kawasaki KLR650 and the Dutch-produced Track T-800CDI).


The displacement is defined as the total volume of air/fuel mixture an engine can draw in during one complete engine cycle. In a piston engine, this is the volume that is swept as the pistons are moved from top dead centre to bottom dead centre. To the layperson this is the "size" of the engine. Motorcycle engines range from less than 50 cc (cubic centimetres), commonly found in many small scooters, to 5735 cc, a Chevrolet V8 engine, currently used by Boss Hoss in its cruiser style motorcycle.

Motorcycles have mostly, but not exclusively, been produced with one to four cylinders, and designers have tried virtually every imaginable layout. The most common engine configurations today are the vertical single and twin, the V-twin, the opposed twin (or boxer), and the in-line triple and in-line four. A number of others designs have reached mass production, including the V-4, the flat 6-cylinder, the flat 4-cylinder, the in-line 6-cylinder, and the Wankel engine. Exotic engines, such as a radial piston engine, sometimes appear in custom built motorcycles.

Engines with more cylinders for the same displacement feel smoother to ride. Engines with fewer cylinders are cheaper, lighter, and easier to maintain. Liquid-cooled motorcycles have a radiator (exactly like the radiator on a car) which is the primary way their heat is dispersed. Coolant or oil is constantly circulated between this radiator and the cylinder when the engine is running. Air-cooled motorcycles rely on air blowing past fins on the engine case to disperse heat. Liquid cooled motorcycles have the potential for greater power at a given displacement, tighter tolerances, and longer operating life, whereas air cooled motorcycles are potentially cheaper to purchase, less mechanically complex and lighter weight.

An air cooled engine contracts and expands with its wider temperature range, requiring looser tolerances, and giving shorter engine life. The temperature range of an air cooled two stroke is even more extreme, and component life even shorter than in an air cooled four stroke.

As applied to motorcycles, two-stroke engines have some advantages over equivalent four-strokes: they are lighter, mechanically much simpler, and produce more power when operating at their best. But four-stroke engines are cleaner, more reliable, and deliver power over a much broader range of engine speeds. In developed countries, two-stroke road-bikes are rare, because - in addition to the reasons above - modifying them to meet contemporary emissions standards is prohibitively expensive. Almost all modern two-strokes are single-cylinder, liquid-cooled, and under 600 cc.

Created By :

- Muhammad Taufan (12062534)
- Ahmad Baidhowi (12062519)
- Adhi Sutanto (12062276)
- Andi Purwantoro (12062523)
- Asep Rosyidin (12062464)